Chemical mechanical polishing apparatus and methods

ABSTRACT

In one aspect, a substrate polishing apparatus is disclosed. The apparatus has a polishing platform having two or more zones, each zone adapted to contain a different slurry component. In another aspect, a substrate polishing system is provided having a holder to hold a substrate, a polishing platform having a polishing pad, and a distribution system adapted to dispense, in a timed sequence, at least two different slurry components selected from a group consisting of an oxidation slurry component, a material removal slurry component, and a corrosion inhibiting slurry component. Polishing methods and systems adapted to polish substrates are provided, as are numerous other aspects.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional Application61/751,688 filed Jan. 11, 2013, and entitled “CHEMICAL MECHANICALPOLISHING APPARATUS AND METHODS” which is hereby incorporated herein forall purposes.

FIELD

The present invention relates generally to semiconductor devicemanufacturing, and more particularly to methods and apparatus adapted topolish a substrate surface.

BACKGROUND

Within semiconductor substrate manufacturing, a chemical mechanicalpolishing (CMP) process may be used to remove various layers, such assilicon, oxides, copper, or the like. Such polishing (e.g.,planarization) may be accomplished by pressing a rotating substrate heldin a holder (e.g., polishing head or carrier) against a rotatingpolishing pad while a slurry is applied ahead of the substrate (e.g.,patterned wafer). The slurry is commonly made up of a mixture ofoxidants, metal oxide abrasive particles, etchants, complexing agents,and corrosion inhibitors. Thus, during polishing, a continuous processof oxidation by oxidants and material removal by abrasive particles andetchants is carried out by the slurry and polishing process. During thispolishing process, precise control of the amount of material removalfrom the substrate is sought. However, given the limitations of existingprocesses, it is difficult to achieve uniformity, especially for removalof small layer thicknesses.

Accordingly, improved polishing apparatus, systems, and methods aresought.

SUMMARY

In a first aspect, a substrate polishing apparatus is provided. Thesubstrate polishing apparatus includes a polishing platform having twoor more zones, each zone adapted to contain a different slurrycomponent.

In another aspect, a substrate polishing system is provided. Thesubstrate polishing system includes a substrate holder adapted to hold asubstrate, and a polishing platform having a moveable polishing pad withtwo or more zones, each zone operable to receive a different slurrycomponent.

In yet another aspect, a method of processing a substrate is provided.The method includes providing a substrate in a substrate holder,providing a polishing platform having a moveable polishing pad, anddispensing a different slurry component into two or more zones on thepolishing pad.

In another aspect, a substrate polishing system is provided. Thesubstrate polishing system includes a substrate holder adapted to hold asubstrate, a polishing platform having a polishing pad moveable relativeto the substrate, and a distribution system adapted to dispense, in atimed sequence, at least two different slurry components selected from agroup consisting of an oxidation slurry component, a material removalslurry component, and a corrosion inhibiting slurry component.

In yet another aspect, a method of processing a substrate is provided.The method includes providing a substrate in a substrate holder,providing a polishing platform having a moveable polishing pad, anddispensing between the polishing pad and the substrate, in a timedsequence, two or more slurry components each having a different chemicalcomposition.

Other features and aspects of the present invention will become morefully apparent from the following detailed description of exampleembodiments, the appended claims, and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a schematic top view of a linear substrate polishingapparatus according to embodiments.

FIG. 1B illustrates a schematic cross-sectioned side view of a linearsubstrate polishing apparatus according to embodiments taken alongsection line 1B-1B of FIG. 1A.

FIG. 1C illustrates a schematic cross-sectioned side view of a linearsubstrate polishing apparatus according to embodiments taken alongsection line 1C-1C of FIG. 1A.

FIG. 2A illustrates a schematic top view of a rotary substrate polishingapparatus according to embodiments.

FIG. 2B illustrates a schematic side view of a rotary substratepolishing apparatus according to embodiments.

FIG. 3A illustrates a top view of a slurry distributor according toembodiments.

FIG. 3B illustrates a side view of a slurry distributor according toembodiments.

FIG. 3C illustrates a first end view of a slurry distributor accordingto embodiments.

FIG. 3D illustrates a second end view of a slurry distributor accordingto embodiments.

FIGS. 3E-3G illustrate various cross section view of a slurrydistributor according to embodiments.

FIG. 4 illustrates a flowchart of a method of polishing a substrateaccording to embodiments.

FIG. 5 illustrates a flowchart of a method of polishing a substrateaccording to embodiments.

FIG. 6 illustrates a graph of phases (e.g., pulses) of a method ofpolishing a substrate according to embodiments.

FIG. 7 illustrates a graph of phases (e.g., pulses) of another method ofpolishing a substrate according to embodiments.

DETAILED DESCRIPTION

Embodiments described herein relate to apparatus, systems and methodsuseful for, and adapted to, polishing a surface of a substrate insemiconductor device manufacturing.

Prior systems have utilized a slurry of mixed slurry components. Thecomponents of the slurry are adapted to accomplish various processes onthe substrate, such as the process of oxidation of the substrate surfaceby oxidants and material removal by abrasive particles and etchants. Ina typical small removal process adapted to remove less than about 250Angstroms, the across the wafer removal variations may be as high as50%-100% of the film thickness that is removed. With advancingtechnology, thinner and thinner films are being applied and may beundergo polishing. For example, films used in the formation of front endstructures, such as inlaid metal gates and the like are very thin. Asthese films are provided in the device structures, it is desired thatthese thin films be removed with a relatively high degree of uniformityand control. Accordingly, as films get thinner, less material removal isaccomplished by the CMP, and more precision is desired in the removalprocess. In the extreme case of atomic layer deposition (ALD), wherefilm thickness is measured in atomic layers (e.g., Angstroms), thematerial removal precision is also desired to be on the order of anatomic layer.

Therefore, there is a need for a polishing apparatus and methods thatenables removal of thin films, wherein such removal is accomplished withvery high uniformity. Furthermore, it is desired that the method canoffer precise control of the removal process, i.e. the relative amountof removal. In one aspect, embodiments of the invention physicallyseparate the slurry components. This may be used to provide more precisecontrol over amount of material removal. By physically (e.g., spatially)separating the slurry components, the polishing process may be providedwith distinct breaks (e.g., formed as physical zones of slurrycomponents having differing chemical composition) between two or more ofthe slurry components (e.g., accomplishing oxidation, material removal,and corrosion inhibition).

For example, in one or more embodiments, a polishing platform (e.g.,comprising a pad support and pad) may be separated to have two or morezones, wherein each zone is adapted to contain a different slurrycomponent. Each slurry component may have a different chemicalcomposition. During polishing, the substrate may be moved rastered(e.g., translated) across the zones wherein each adjacent zone includesa different slurry component. Running one cycle across the zones, insequence, may be used to effectively remove one atomic layer, forexample. Total material removal can be precisely controlled by managingthe number of cycles. Removal may be controlled on an atomic level.

In one or more embodiments, the polishing surface is separated (e.g.,broken up) into multiple zones, wherein each zone contains an individualslurry component that performs one of an oxidation, material removal, orcorrosion inhibition process. By rastering (e.g., scanning) across theseseparated zones, high cycle counts can be achieved within reasonabletotal polish time. For example, within an oxidation zone containing theoxidation slurry component, oxidants function to oxidize the surfacelayer of substrate. This oxidation process may be self-limiting, sinceonly a surface layer is exposed to oxidants. Within the material removalzone containing, for example, the removal and etchant slurry component,abrasives and etchants attack the previously-oxidized surface layer. Thematerial removal zone may be adjacent to the oxidation zone. Thismaterial removal process may also be self-limiting, since only theoxidized layer is removed. A corrosion inhibiting zone containing acorrosion inhibiting slurry component (e.g., including corrosioninhibiters) operates on the previously abraded surface layer to limitcorrosion thereof. The corrosion inhibiting zone may be providedadjacent to the oxidation zone.

In another aspect, rather than being separated physically, theapplication of the slurry components are separated in time. Thus, in oneaspect, embodiments of the invention disclose a polishing process (e.g.,a film removal process), which utilizes multi-step reactions to affectuniform film removal. In particular, embodiments of the inventionseparate the slurry components in time by introducing them separatelyand in a timed sequence. This may be used to provide more precisecontrol over amount of material removal. This multi-step polishingprocess can be applied to any application where the CMP involvescompeting reactions.

Thus, in this aspect, the polishing process will have distinct breaks(e.g., separations in time) between administering of the various slurrycomponents used to accomplish oxidation, material removal, and/orcorrosion inhibition processes. In one or more embodiments, theoxidiation slurry component may be first introduced in time, followed bya material removal slurry component (e.g., containing abrasives and/oretchants). This may be followed in sequence by introducing a corrosioninhibitor slurry component in some embodiments. The sequence may befollowed by introduction of a rinsing liquid (e.g., de-ionized (DI)water) in some embodiments. In other embodiments, the rinsing liquid maybe introduced between the various slurry introductions phases. Theseslurry components may be administered between the substrate and thepolishing pad during the polishing process, as will be further explainedherein.

These and other aspects of embodiments of the invention are describedbelow with reference to FIGS. 1A-7 herein.

FIGS. 1A-1C illustrate various views of a substrate polishing apparatus100 and components thereof. The substrate polishing apparatus 100 isadapted to hold and polish a substrate 101 as will be apparent from thefollowing description. The substrate polishing apparatus 100 includes apolishing platform 102 having two or more physical zones, such as firstzone 104, second zone 106, and third zone 108. The two or more zones(e.g., 104, 106, and 108) are adapted to contain a different slurrycomponent having a different chemistry (chemical composition). The twoor more zones may be arranged across a width “W” of the platform 102. Inthe depicted embodiment, nine zones are shown. However, more or lessnumbers of zones may be provided. There may be multiple zones that arenon-adjacent, but that contain a slurry component having the samechemistry. In the depicted embodiment, the platform 102 comprises alinear polishing platform wherein the two or more zones are arrangedacross a width “W” of a pad 109 and that extend along the length “L” ofthe pad with the length L being substantially longer than the width W.In the depicted embodiment, the pad 109 of the platform 102 moveslinearly as indicated by directional arrow 110.

During the polishing method, various slurry components, such as slurrycomponent 1, slurry component 2, and slurry component 3 may be appliedto the pad 109 by a distributor 112. The distributor 112 may have anysuitable internal structure capable of dispensing the slurry componentsto the two or more zones (e.g., to zones 104, 106, 108). The slurrycomponent 1, slurry component 2, and slurry component 3, for example,may be received from slurry component supplies 114, 116, 118,respectively. More or less numbers of slurry components may be provided.The supply of slurry components to the distributor 112 may beaccomplished by a distribution system having one or more suitable pumpsor other flow control mechanisms 115. “Slurry component” as used hereinmeans a processing medium that is adapted to carry out one or moredesignated polishing functions. In some embodiments, a rinsing liquid(e.g., de-ionized water) may be provided from the rinsing liquid source123 and inserted between two or more of the zones, such as between zone104 and 106, or between 106 and 108, or between both zones 104 and 106and zones 106 and 108. Any suitable construction of the distributor 112may be used to accomplish this separation of the zones 104, 106, 108 bya rinsing liquid zone.

For example, slurry component 1 may comprise a material adapted toexecute a surface modification function, such as oxidation or othersurface modification such as the formation of a nitride, bromide,chloride, or hydroxide containing later. Slurry component 1 may containa liquid carrier such as purified water, and an oxidant such as hydrogenperoxide, ammonium persulfate, or potassium iodate. Other surfacemodifying materials may be used. Slurry component 1 may be supplied tothe first zone 104 of the pad 109 from the component supply 1 114through a first channel 119A (FIG. 3G) of the distributor 112, forexample.

Slurry component 2 may comprise a material adapted to execute a materialremoval function. Slurry component 2 may contain a liquid carrier suchas purified water, and abrasive media such as silicon dioxide oraluminum oxide. The abrasive may have an average particle size betweenabout 20 nanometers and 0.5 microns. Other particle sizes may be used.Slurry component 2 may also include an etchant material such ascarboxylic acid, or an amino acid. Other etchant or complexing agentmaterials may be used. Slurry component 2 may be supplied from thecomponent supply 2 116 to the second zone 106 of the pad 109 by a secondchannel 119B (FIG. 3F) of the distributor 112, for example.

In one or more embodiments, slurry component 3 may comprise a materialadapted to execute a corrosion inhibition function. Slurry component 3may contain a liquid carrier such as purified water, and corrosioninhibitor such as benzotriazole, or 1,2,4 Triazole. Slurry component 3may be supplied from the component supply 3 118 to the third zone 108 ofthe pad 109 by a third channel 119C (FIG. 3E) of the distributor 112,for example.

The zones 104, 106, 108 may be arranged in a side by side fashion andmay each have a width of between about 2 mm and 50 mm. The widths may bethe same as or different from each other. Other widths may be used.

In one or more embodiments, a distribution system including adistributor 112 is adapted to dispense into the two or more zones (e.g.,zone 104, 106) at least two different slurry components. The slurrycomponents may be selected from a group consisting of a surfacemodification slurry component, and a material removal slurry component,as discussed above.

In one or more embodiments, the distributor 112 may be formed as aunitary component and may be positioned adjacent to the pad 109 (e.g.,just above the pad 109). The distributor 112 may provide delivery of theslurry components concurrently through two or more outlets (e.g.,through outlets 121A, 121B, and 121C). For example, as shown in FIG.3A-3G, the distributor 112 may be part of a distribution system that mayinclude multiple channels, such as a first channel 119A extending alonga length of the distributor body 117. First channel 119A is adapted todistribute the slurry component 1 from component 1 supply 114 to one ormore first distribution outlets 121A that are fluidly coupled to thefirst channel 119A along its length.

The distributor 112 may also include a second channel 119B extendingalong the length of the distributor body 117 and adapted to distributethe slurry component 2 from component 2 supply 116 to one or more seconddistribution outlets 121B that are fluidly coupled to the second channel119B along its length.

The distributor 112 may also include a third channel 119C extendingalong the length of the distributor body 117 and adapted to distributethe slurry component 3 from component 3 supply 118 to one or more seconddistribution outlets 121C that are fluidly coupled to the third channel119C along its length. Other channels and interconnected outlets may beprovided to disburse other slurry components and/or a rinsing liquid.

In some embodiments, the rinsing liquid may be received in a separateseparation zone to separate the disbursed slurry components. The outlets121A, 121B, 121C may have a diameter of less than about 5 mm, or betweenabout 1 mm and 15 mm in some embodiments. A pitch (e.g., spacing betweenthe adjacent outlets) may be less than about 50 mm, less than about 25mm, or even less than about 10 mm in some embodiments. In someembodiments, the pitch may be between about 2 mm and 50 mm. Otherdiameters and pitches may be used.

In other embodiments, the distributor may be comprised of separatedistributor heads, one for each slurry component that may be arranged atdifferent spatial locations on the pad 109. A rinsing liquid (e.g., DIwater) may be delivered through some or all of the outlets 121A-121C, orthrough separate outlets specifically designed for the rinsing liquid.Rinsing liquid may be provided from rinsing liquid supply 123 to some orall of each of the outlets 121A-121C by controlling valve 119S.Optionally, the rinsing liquid may be provided by a separate distributorhead or separate outlets from the distributor 112.

In another embodiment, the distributor may be included in the padsupport 127 of the platform 102. In this embodiment, the slurrycomponents 1, 2, 3 may be disbursed to the various zones 104, 106, and108 from underneath the pad 109. The pad support 127 may include holeslike the outlets 121A-121C in distributor 112 being arranged across thewidth of the pad 109. Each hole may be fluidly coupled to one of theslurry component supplies 114, 116, 118. The various separated slurrycomponents 1, 2, 3 may pass though the holes and wick through the pad109 containing an internal porous structure of connected open pores asthe pad 109 is rotated on the rollers 124, 126. The wicking provides theslurry components 1, 2, 3 to the one or more zones 104, 106, 108,respectively. Rinsing liquid may also be disbursed through some or allof the holes.

Again referring to FIGS. 1A-1C, as the slurry components are beingsupplied to the zones 104, 106, 108 of the pad 109, a substrate holder120 of the substrate polishing apparatus 100 may be rotated. Substrateholder 120 is adapted to hold the substrate 101 in contact with the pad109 and rotate the substrate 101 as the polishing takes place. Othermotions may be provided in addition or in place of the rotation, such asorbital motion. Rotational speed may be between about 10-150 RPM, forexample. Rotation may be accomplished by driving the holder 120 with aholder motor 122. Any suitable motor may be used. An applied pressure onthe substrate 101 during polishing may be between about 0.1 psi and 1psi, for example. Any suitable conventional mechanism for applying thepressure may be used, such as a spring-loaded mechanism or othersuitable vertically-acting actuator. Other rotational speeds andpressures may be used. Substrate holders (also referred to as retainersor carrier heads) are described in U.S. Pat. No. 8,298,047; U.S. Pat.No. 8,088,299; U.S. Pat. No. 7,883,397; and U.S. Pat. No. 7,459,057,issued to the present assignee, for example.

As the slurry components 1, 2, 3 are applied to the respective zones104, 106, 108, the pad 109 may be moved in the direction of the arrow110. The linear speed of movement of the pad 109 in the direction ofarrow 110 may be between about 40 cm/sec and about 600 cm/sec, forexample. Other speeds may be used. The pad 109, as best shown in FIGS.1B and 1C, may be provided in the form of a continuous or endless belt.The pad 109 may be supported at its ends by first and second rollers124, 126 (e.g., cylindrical rollers) and underneath the top portion ofthe pad 109 by a pad support 127 spanning the width of the pad 109.Rollers 124, 126 may be supported for rotation on a frame 128 bybearings or bushings, or other suitable low friction devices, forexample. One of the rollers, such as roller 126, may be coupled to a paddrive motor 130 which may be driven at the appropriate rotational speedto accomplish the linear polishing speed of the pad 109 described above.Pad support 127 may also be coupled to the frame 128 at one or morelocations and may support the upper portion of the pad 109 underneathsome or most of the length L of upper surface of the pad 109.

In addition to the rotation of the substrate holder 120, and the motionof the pad 109, the holder 120 may be translated in the direction ofdirectional arrow 132. The translation may be an oscillation back andforth along the transverse direction 132, generally perpendicular to thelinear motion of the pad 109. Translation may be caused by any suitabletranslation motor 134 and drive system (not shown) that moves thesubstrate holder 120 back and forth along a support beam 136. The drivesystem adapted to accomplish the translation may be a rack and pinion,chain and sprocket, belt and pulley, drive and ball screw, or othersuitable drive mechanism. In other embodiments, an orbital motion may beprovided by a suitable mechanism. The rotation of the pad 109, rotationand translation (e.g., oscillation) of the substrate holder 120, and thedistribution flow of the slurry components 1, 2 and 3 and rinsing liquid123 may be controlled by controller 138. Controller 138 may be anysuitable computer and connected drive and/or feedback components adaptedto control such motions and functions.

The pad 109 may be made of a suitable polishing pad material, forexample. The pad 109 may be a polymer material, such as polyurethane,and may have open surface porosity. Surface porosity may be openporosity and may have an average pore size of between about 2 micronsand 100 microns, for example. Pad may have a length L, as measuredbetween the centers of the rollers 124, 126, of between about 30 cm and300 cm, for example. Other dimensions may be used.

FIGS. 2A and 2B illustrate various views of an alternative embodiment ofa substrate polishing apparatus 200 and components thereof. As before,the substrate polishing apparatus 200 is adapted to hold and polish asubstrate 101 as will be apparent from the following description. Thesubstrate polishing apparatus 200 includes a polishing platform 202having a pad 209 and a pad support 227 (e.g., a platen). The polishingplatform 202 has two or more physical zones, such as first zone 204, andsecond zone 206, and even a third zone 208. Zones 204, 206, 208 in thisembodiment are arranged as concentric annuli, and the platform 202 isrotatable.

Each zone 204, 206, 208 is adapted to contain a different slurrycomponent having a different chemistry, such as slurry components 1-3described above. The slurry components may be dispensed to the variouszones 204, 206, 208 by a distributor 212 coupled to the componentsupplies 114, 116, 118, via valves or other flow control mechanism ascommended by controller 238 as described before. The two or more zones204, 206, 208 may be arranged across a diameter “D” of the platform 202.The width of each annular zone may be the same or different and of awidth, and may be as described above. In the depicted embodiment, nineannular zones are shown. However, more or less numbers of zones may beprovided. Furthermore, there may be multiple zones that are not adjacentto each other, but that contain a slurry component having a samechemistry (e.g., chemical composition). For example, each of the zoneslabeled 204 may receive and contain the same slurry chemistry. Each ofthe zones labeled 206 may receive and contain the same slurry chemistry,and each of the zones labeled 208 may receive and contain the sameslurry component chemistry. However, the chemistries in each of thezones 204, 206 and 208 may have different slurry component chemistriesas compared to each other.

In the depicted embodiment, the platform 202 comprises a rotarypolishing platform wherein the two or more zones (e.g., zones 204, 206or 204, 206 and 208) are arranged across a diameter D the pad 209. Theplatform 202 and pad 209 may be rotated in the direction of directionalarrow 210 at rotational speed of between about 10 and about 200 RPM by aplatform motor 230. As before, the substrate holder 220 may be rotatedby a suitable holder motor 222 to rotate the substrate 101 as thepolishing takes place. Rotational speed of the holder 220 may be betweenabout 10 RPM-200 RPM, for example. Similarly, the holder 220 may betranslated (e.g., oscillated) back and forth along the transversedirection 232, generally perpendicular to the tangential motion of thepad 209. Translation may be caused by any suitable translation motor 234and drive system (not shown) as described above.

An applied pressure on the substrate 101 during polishing may be asdiscussed above, for example. Any suitable conventional mechanism forapplying the pressure may be used, such as a spring-loaded mechanism oractuator. Other rotational speeds and pressures may be used. Substrateholder 220 may be as described in U.S. Pat. No. 8,298,047; U.S. Pat. No.8,088,299; U.S. Pat. No. 7,883,397; and U.S. Pat. No. 7,459,057, forexample.

FIG. 4 illustrates a method 400 of processing a substrate (e.g.,substrate 101), and in particular a method of polishing a surface (e.g.,a front side or backside surface) of a substrate 101 (e.g., a patternedor unpatterned wafer). The method 400 includes, in 402, providing asubstrate in a substrate holder (e.g., substrate holder 120, 220),providing, in 404, a polishing platform (e.g., polishing platform 102,202) having a moveable polishing pad (e.g., polishing pad 109, 209),and, in 406, dispensing a different slurry component into two or morezones (e.g., zones 104, 106, 108) on the polishing pad. The polishingpad may be of the linear moving version 109 or rotationally movingversion 209. The slurry components may be disbursed to the zones (e.g.,zones 104, 106, 108) above the pad 109 or below the pad 109 (e.g., bywicking or other capillary action).

In another aspect, a substrate polishing system is provided as describedin either of FIGS. 1A-1C or 2A and 2B. The substrate polishing system100, 200 includes a polishing holder 120, 220 adapted to hold asubstrate 101, a polishing platform 102, 202 having a polishing pad 109,209 moveable relative to the substrate 101, and a distribution systemadapted to dispense at least two different slurry components selectedfrom a group consisting of an oxidation slurry component, a materialremoval slurry component, and a corrosion inhibiting slurry component.In this aspect, rather than being distributed into zones arranged acrossthe width W or diameter D of the pad 109, 209, the two or more slurrycomponents are dispensed in a timed sequence, one after another.

In accordance with this aspect, a first slurry component selected fromthe group consisting of an oxidation slurry component, a materialremoval slurry component, and a corrosion inhibiting slurry component isfirst dispensed onto the pad (e.g., pad 109, 209). After a predeterminedamount of time has elapsed, the supply of the first slurry component isstopped, and a second slurry component selected from the groupconsisting of an oxidation slurry component, a material removal slurrycomponent, and a corrosion inhibiting slurry component is then dispensedonto the pad (e.g., pad 109, 209). After another predetermined amount oftime has elapsed, the supply of the second slurry component is stopped,and a third slurry component selected from the group consisting of anoxidation slurry component, a material removal slurry component, and acorrosion inhibiting slurry component may then dispensed onto the pad(e.g., pad 109, 209). After a third predetermined amount of time haselapsed, the timed sequence may start over again by again dispensing thefirst slurry components. The sequence may be repeated as many times asnecessary to accomplish the desired results, such as a desired amount offilm removal. Following the polishing sequence, the pad 109, 209 may berinsed by supplying rinsing liquid thereto.

FIGS. 5 and 6 illustrate another method 500 of polishing a substrate.The method 500 includes, in 502, providing a substrate (e.g., substrate101) in a substrate holder (e.g., holder 120, 220), and, in 504,providing a polishing platform having a moveable polishing pad. In 506,the method includes dispensing, in a timed sequence, two or more slurrycomponents each having a different chemical composition between thepolishing pad and the substrate.

As shown in FIG. 6, the slurry components may be dispersed between thepad (e.g., pad 109, 209) and the substrate 101 in a timed sequence asshown. In a first time increment 650, a first slurry component (e.g., anoxidizing slurry component) may be supplied. This is followed by asecond slurry component (e.g., a material removal slurry component) fora second time increment 651. The chemical composition of the first andsecond slurry components are different. This may be followed byproviding a third slurry component (e.g., a corrosion inhibiting slurrycomponent) for a third time increment 652. Two or more of thesedispensing phases may be repeated in 653-655. Other phases may beperformed in addition or in substitution thereof. The three- or moredispense sequences may be repeated over and over as many times aredesired on a single substrate. This may be performed while the substrateis being oscillated and rotated against the moving pad (e.g., pad 109,209) as described above. After these polishing phases are completed, thepad (e.g., pad 109, 209) may undergo a rinsing phase wherein the pad(e.g., pad 109, 209) may be supplied with a rinsing liquid (e.g., DIwater or other inert liquid solution) in 656. The disbursing of therinsing liquid (e.g., de-ionized water) may be used to dilute the lastapplied chemistry. The method 500 may then stop, a new substrate may beplaced in the substrate holder (e.g., substrate holder 120, 220), andthe described method 500 may be implemented on the second substratestarting at 657.

Each of the phases may take between about 1 second and about 60 seconds.Other time lengths may be used. Some of the pulses may be less than 1second. Each phase may be of the same or a different length. Some of theslurry components may be combined in some embodiments to institute morethan one processing phase in a single pulse. For example, an oxidationand corrosion inhibitor phase may be combined as one slurry componentand provided as one pulse in some embodiments. In other embodiments, acomplexing agent may be combined in a single pulse with an abrasive(e.g., a metal oxide abrasive). The oxidizing agent may be hydrogenperoxide. The corrosion inhibitor may be triazole. The complexing agentmay be an organic acid, organic acid salt, or an amino acid. Other typesof oxidizing agents, corrosion inhibitors, complexing agents, andabrasives may be used.

FIG. 6 illustrates another embodiment of a method 600 utilizing a seriesof slurry components that are disbursed in a timed sequence (e.g., aspulses of individual slurry components). The use of time-separatedintroduction of polishing chemistry allows for increased flexibility inuse of chemical agents (e.g., two or more slurry components). Forexample, oxidation chemistries are generally self-limiting. A surfacefilm may be oxidized to a depth of about 20 angstroms and then stopped.By separating the slurry components in time, more aggressive oxidationchemistries could be used where the depth of oxidation may be controlledby the length of the pulse of chemical slurry component supplied to thesubstrate.

In particular, individual phases may be instituted to affect specificreactions to form a modified layer on the surface of the substrate. Insome conventional material removal processes, systems use slurryadditives which may suppress removal at lower polishing pressures. Theseprior polishing systems may provide better control of within die (WID)thickness because removal rates drops dramatically once topography hasbeen removed. As a result, topography in regions of a die with lowdensity is quickly removed and then the dielectric removal stops whiletopography removal in other regions of the die continues to polish untilthey are planarized. However, these systems suffer from very low removalrates (by design) once the main topography has been planarized. They mayalso suffer from large features being incompletely removed. A multi-stepmethod according to an aspect of the invention having phased (e.g.,timed) introduction of the slurry components (e.g., additive, abrasivewithout additive, and possibly interspersed and/or followed by a rinse)may be use to overcome these previous limitations. For example, theadditive could be first introduced, followed by an abrasive solutionwhich dilutes the additive and enables limited film removal. Additionalremoval could be accomplished by introduction of rinse which may quicklydilute the additive and allows limited removal of film until the chargeof abrasive slurry component is exhausted.

An example of the multi-step method and system is provided below. Themethod may be useful for metal film removal, and may involve anoxidation phase involving film oxidation, and a phase of inhibitoradsorption and complexing agent aided abrasion of the oxidized surface,which are executed in a serial manner to achieve film removal perreaction cycle. In this embodiment, each of the slurry components may bedispersed between the pad (e.g., pad 109, 209) and the substrate 101 ina timed sequence, but with a rinsing phase being instituted between thedisbursement of each slurry component, as shown in FIG. 7. Thus, eachpulse of a slurry component (e.g., oxidizing, inhibitor, complexingagent, material removal agent) may be separated by a pulse of a rinsingagent (e.g., DI water) to rinse the surface of the pad (e.g., pad 109,209) and substrate 101.

In particular, in a first time increment 650, a first slurry component(e.g., an oxidizing slurry component) may be supplied. This is followedby a rinse in 657. Then a second slurry component (e.g., a materialremoval slurry component) may be disbursed for a second time increment652. This may be followed by another rinse in 657. The chemicalcomposition of the first and second slurry components are different.This second rinse 657 may be followed by a third slurry component (e.g.,a corrosion inhibiting slurry component) for a third time increment 653.This may be followed by another rinse in 657. After this sequence iscompleted, it may be repeated again on the same substrate 101 as manytimes as desired to achieve the desired material removal, or a newsubstrate may be inserted in the substrate holder (e.g., 120, 220) andpolishing of the substrate by the method 700 may commence on the newsubstrate. The times may be the same or different for each phase of thepolishing process.

Other steps may be used in the sequence, such as an inhibitor adsorptionphase, and complexation-abrasion phase. Two or more of the phases may becombined in some embodiments. The relative duration of each phase may bedetermined based on reaction kinetics of that particular phase. Forexample, an oxidation phase may be relatively short for copper polish,while it may be relatively long for polishing ruthenium or more noblemetals. The pulse duration of a corrosion inhibitor phase (includinginhibitor adsorption) may also be varied in length based on the kineticsof adsorption. Likewise, a complexation-abrasion phase may be varied inlength based on the kinetics thereof. In some embodiments, a pulse of anoxidizing slurry component (e.g., an oxidizing solution) may be followedby a pulse of a corrosion inhibitor slurry component (e.g., an inhibitorsolution), and then followed by a pulse of a complexing slurry component(e.g., a complexing agent). These sequenced pulses may be provided whilethe substrate 101 is being pressed against a moving surface of the pad(e.g., pad 109, 209).

Another example of a phased instruction of the slurry components in atimed sequence is as follows. A copper film removal process is providedwherein a first pulse of combined slurry component of an oxidizer andinhibitor solution are followed by a separate pulse of a complexingagent, while the substrate (e.g., wafer) is being pressed against amoving surface of the pad (e.g., pad 109, 209) as described herein. Insome embodiments, the pulse of combined slurry components of oxidizerand inhibitor solution and the separate pulse of complexing agent may beinterspersed by a rinsing pulse of a rinsing liquid. Optionally, therinse pulse may be at the end of the two-phase sequence.

In another method embodiment adapted to metal oxide film polishing andremoval, a two-phase method includes a first pulse of an oxidizingslurry component that may be followed by a separate sequential pulse ofa combined slurry component having a metal oxide abrasive and acomplexing agent. Optionally, the complexing agent slurry component andthe metal oxide abrasive slurry component may be instituted as separatedphases one after the other in a three-phase polishing process. A rinsingphase may be instituted between the phases or at the end of thesequence.

One significant advantage of the time sequence introduction of slurrycomponents is that each step or pulse may be self-limiting, which maylead to relatively more uniform removal of even small thicknesses,particularly less than 500 Angstroms, and especially less than 200Angstroms. For example, once a surface oxidation phase of a surface(e.g., a copper surface) is completed to several atomic layers (betweenabout 25-30 Angstroms), the oxidation rate may slow dramatically.Consequently, when the complexation-abrasion phase is next executed,film removal may be automatically limited to about 25 to 30 Angstroms,regardless of the length of the phase and film removal uniformity may bemade to be relatively independent of removal rate.

In each of the described methods herein, the distribution of the slurrycomponents may be provided by the systems and apparatus describedherein. Optionally, other suitable systems adapted to carry out a timedsequence delivery of the slurry components, and possibly a rinse, may beused. Accordingly, while the present invention has been disclosed inconnection with example embodiments thereof, it should be understoodthat other embodiments may fall within the scope of the invention, asdefined by the following claims.

The invention claimed is:
 1. A substrate polishing apparatus,comprising: a polishing platform having two or more zones, each zoneadapted to contain a different slurry component.
 2. The substratepolishing apparatus of claim 1, comprising a linear polishing platformwherein the two or more zones are arranged across a width.
 3. Thesubstrate polishing apparatus of claim 1, comprising a rotary polishingplatform wherein the two or more zones are arranged as concentricannuli.
 4. The substrate polishing apparatus of claim 1, comprising adistributor adapted to dispense at least two of the different slurrycomponents to the two or more zones.
 5. The substrate polishingapparatus of claim 4, wherein the distributor includes a first set ofoutlets adapted to disburse a first slurry component to one of the twoor more zones, and a second set of outlets adapted to disburse a secondslurry component to another of the two or more zones.
 6. The substratepolishing apparatus of claim 1, wherein each zone has a width of about 2mm or more.
 7. The substrate polishing apparatus of claim 1, wherein afirst zone has only an oxidation slurry component dispensed therein. 8.The substrate polishing apparatus of claim 1, wherein a second zone hasonly a material removal slurry component dispensed therein.
 9. Thesubstrate polishing apparatus of claim 1, wherein a third zone has onlya corrosion inhibition slurry component dispensed therein.
 10. Thesubstrate polishing apparatus of claim 1, wherein a first zone and asecond zone include slurry components having different chemicalcompositions.
 11. The substrate polishing apparatus of claim 1,comprising a distribution system adapted to dispense into the two ormore zones at least two different slurry components selected from agroup consisting of: a surface modification slurry component, and amaterial removal slurry component.
 12. The substrate polishing apparatusof claim 1, wherein a rinsing liquid zone is dispensed between the twoor more zones.
 13. A substrate polishing system, comprising: a substrateholder adapted to hold a substrate; and a polishing platform having amoveable polishing pad with two or more zones, each zone operable toreceive a different slurry component.
 14. A method of polishing asubstrate, comprising: providing a substrate in a substrate holder;providing a polishing platform having a moveable polishing pad; anddispensing a different slurry component into two or more zones on thepolishing pad.
 15. A substrate polishing system, comprising: a substrateholder adapted to hold a substrate; a polishing platform having apolishing pad moveable relative to the substrate; and a distributionsystem adapted to dispense, in a timed sequence, at least two differentslurry components selected from a group consisting of a surfacemodification slurry component, and a material removal slurry component.16. The system of claim 15, wherein the surface modification slurrycomponent comprises an oxidation slurry component.
 17. The system ofclaim 15, wherein the distribution system is adapted to dispense, in atimed sequence, a corrosion inhibiting slurry component.
 18. The systemof claim 15, wherein the distribution system is adapted to dispense arinsing liquid, in a timed sequence, between the surface modificationslurry component and the material removal slurry component.
 19. A methodof polishing a substrate, comprising: providing a substrate in asubstrate holder; providing a polishing platform having a moveablepolishing pad; and dispensing between the polishing pad and thesubstrate, in a timed sequence, two or more slurry components eachhaving a different chemical composition.
 20. The method of claim 19,wherein the two or more slurry components are selected from a groupconsisting of: a surface modification slurry component, and a materialremoval slurry component.